content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.flowable.internal.operators;
  
  import java.util.concurrent.atomic.*;
  
  import org.reactivestreams.*;
  
  import hu.akarnokd.reactivestreams.extensions.RelaxedSubscriber;
  import io.reactivex.common.exceptions.Exceptions;
  import io.reactivex.common.functions.BiFunction;
  import io.reactivex.common.internal.functions.ObjectHelper;
  import io.reactivex.flowable.Flowable;
  import io.reactivex.flowable.internal.subscriptions.SubscriptionHelper;
  import io.reactivex.flowable.subscribers.SerializedSubscriber;
  
  public final class FlowableWithLatestFrom<T, U, R> extends AbstractFlowableWithUpstream<T, R> {
      final BiFunction<? super T, ? super U, ? extends R> combiner;
      final Publisher<? extends U> other;
      public FlowableWithLatestFrom(Flowable<T> source, BiFunction<? super T, ? super U, ? extends R> combiner, Publisher<? extends U> other) {
          super(source);
          this.combiner = combiner;
          this.other = other;
      }
  
      @Override
      protected void subscribeActual(Subscriber<? super R> s) {
          final SerializedSubscriber<R> serial = new SerializedSubscriber<R>(s);
          final WithLatestFromSubscriber<T, U, R> wlf = new WithLatestFromSubscriber<T, U, R>(serial, combiner);
  
          serial.onSubscribe(wlf);
  
          other.subscribe(new FlowableWithLatestSubscriber(wlf));
  
          source.subscribe(wlf);
      }
  
      static final class WithLatestFromSubscriber<T, U, R> extends AtomicReference<U> implements RelaxedSubscriber<T>, Subscription {
  
          private static final long serialVersionUID = -312246233408980075L;
  
          final Subscriber<? super R> actual;
          final BiFunction<? super T, ? super U, ? extends R> combiner;
  
          final AtomicReference<Subscription> s = new AtomicReference<Subscription>();
  
          final AtomicLong requested = new AtomicLong();
  
          final AtomicReference<Subscription> other = new AtomicReference<Subscription>();
  
          WithLatestFromSubscriber(Subscriber<? super R> actual, BiFunction<? super T, ? super U, ? extends R> combiner) {
              this.actual = actual;
              this.combiner = combiner;
          }
          @Override
          public void onSubscribe(Subscription s) {
              SubscriptionHelper.deferredSetOnce(this.s, requested, s);
          }
  
          @Override
          public void onNext(T t) {
              U u = get();
              if (u != null) {
                  R r;
                  try {
                      r = ObjectHelper.requireNonNull(combiner.apply(t, u), "The combiner returned a null value");
                  } catch (Throwable e) {
                      Exceptions.throwIfFatal(e);
                      cancel();
                      actual.onError(e);
                      return;
                  }
                  actual.onNext(r);
              }
          }
  
          @Override
          public void onError(Throwable t) {
              SubscriptionHelper.cancel(other);
              actual.onError(t);
          }
  
          @Override
          public void onComplete() {
              SubscriptionHelper.cancel(other);
              actual.onComplete();
          }
  
          @Override
          public void request(long n) {
              SubscriptionHelper.deferredRequest(s, requested, n);
          }
  
          @Override
          public void cancel() {
              SubscriptionHelper.cancel(s);
              SubscriptionHelper.cancel(other);
          }
  
          public boolean setOther(Subscription o) {
              return SubscriptionHelper.setOnce(other, o);
          }
  
          public void otherError(Throwable e) {
              SubscriptionHelper.cancel(s);
              actual.onError(e);
          }
      }
  
      final class FlowableWithLatestSubscriber implements RelaxedSubscriber<U> {
          private final WithLatestFromSubscriber<T, U, R> wlf;
  
          FlowableWithLatestSubscriber(WithLatestFromSubscriber<T, U, R> wlf) {
              this.wlf = wlf;
          }
  
          @Override
          public void onSubscribe(Subscription s) {
              if (wlf.setOther(s)) {
                  s.request(Long.MAX_VALUE);
              }
          }
  
          @Override
          public void onNext(U t) {
              wlf.lazySet(t);
          }
  
          @Override
          public void onError(Throwable t) {
              wlf.otherError(t);
          }
  
          @Override
          public void onComplete() {
              // nothing to do, the wlf will complete on its own pace
          }
      }
  }
  